Short answers, pulled from the story.
John Ledford founded Sentai Filmworks in 2008. Ledford had previously co-founded A.D. Vision on the 17th of August 1992, together with Matt Greenfield, before ADV collapsed and its assets were liquidated in 2009.
Sentai Filmworks is one of five successor companies to ADV Films, alongside Section23, Switchblade Pictures, Maiden Japan, and AEsir Holdings. John Ledford founded Sentai in 2008 and acquired the majority of ADV's titles before ADV formally went defunct on the 1st of September 2009.
Sentai Filmworks is owned by AMC Global Media, formerly known as AMC Networks, which acquired Sentai and its parent company Sentai Holdings, LLC on the 5th of January 2022. The acquisition also included the HIDIVE streaming service and the Anime Network.
Sentai Filmworks launched a GoFundMe campaign on the 18th of July 2019, following the arson attack on Kyoto Animation, with a target of US$750,000. Donations surpassed one million dollars within the first 24 hours, and the campaign closed at $2,370,910.
Akame ga Kill! premiered on Adult Swim's Toonami block on the 8th of August 2015, drawing over 1.8 million viewers, making it one of the most watched programs in the block's history at that time. Parasyte -the maxim- followed on Toonami on October 3 of the same year.
Sentai Filmworks has no relation to the Super Sentai media franchise despite sharing the name. The company has no involvement in any international distribution of that franchise.